Hurricane Michael weakened on Thursday as it churned far from land in the middle of the Atlantic Ocean with no expected threat to land, US forecasters said.

Michael had earlier swelled to become this year's first category three storm on the five-point Saffir-Simpson scale.

It dropped to a category two hurricane with top winds gusting at 110 miles (177 kilometers) per hour, according to the Miami-based National Hurricane Center.

Michael was swirling about 945 miles west-southwest of the Azores as it moved north-northeastward at six miles per hour, the NHC said in its 2100 GMT.

There were no coastal watches or warnings in effect, and the NHC said Michael would gradually weaken over the next 48 hours.

Hurricane Leslie, a category one storm cycling closer to North America, was stationary some 430 miles south-southeast of Bermuda, where the local weather service issued a tropical storm watch for the British overseas territory.

Its top winds were near 75 miles per hour, making Leslie a category one hurricane.

"No significant change in strength is anticipated tonight, but Leslie will likely begin to intensify on Friday," the NHC said.

It warned that swells generated by Leslie in Bermuda, the US East Coast from central Florida northward, the northern Leeward Islands, Puerto Rico and the Virgin Islands "could cause life-threatening surf and rip current conditions."